Telephone systems typically provide an analog signal path for voice communication from one telephone subscriber to another. In such systems a customer's telephone is assigned a Directory Number (DN), for example, a 3 digit exchange code and a 4 digit number. The telephone is connected through telephone lines to a telephone switching center whose function is to interconnect the telephone of the calling subscriber to the telephone of the called subscriber. The switching center, which comprises large banks of electromechanical switches, completes the physical connection to the telephone of the called party. An alternating current ranging signal is sent to the called telephone along with a direct current signal supplied generally from a battery at the switching center. The function of the ringing signal is to cause a bell to ring at the called telephone. The called party then lifts the "receiver" from the hook. The act of lifting the hook closes a pair of contacts, which in turn causes the customer loop back to the switching center to be completed. Since the customer loop is completed back to the switching center, the "Off-Hook" state is detected at the center by monitoring the direct current from the battery. Detecting the "Off-Hook" status causes the ring signal to terminate and permits voice communication over the customer loop. If the called party is connected to a different exchange, the local switching center first connects to the remote switching center and the remote center completes the call.
Most state of the art telephone systems replaced the electromechanical switching units with stored program digital computers. This newer equipment, generally referred to as a Stored Program Control Switching System or an SPCS unit, in addition to performing all of the functions of the earlier switching centers, the SPCS units, allow the telephone companies to provide various additional functions that may prove useful to many customers.
The advent of digital computers also created the desire to transmit digital data between telephone system customers. A typical state of the art telephone system must now service various communication products at the customer's premises. This equipment is referred to as Customer Premises Equipment (CPE) and includes products for handling voice communications or data communications. The term Data Terminal Equipment (DTE) is used generically in referring to "Dumb" terminals, Intelligent Work Stations (IWS), etc. The communications link carrying digital data is typically the telephone voice channel that basically was designed for voice communication between the calling customer and the called customer. The telephone system does however serve effectively for both voice and data applications. To transmit binary data, the binary data signal is converted from a digital format to an analog format by a modulator. At the receiver end, a demodulator extracts the binary data from the transmitted signal. Any CPE connected to the phone line must go through a Data Access Arrangement (DAA) which provides protection for the CPE from line transients. All CPE and DAA must meet FCC specifications to avoid the CPE disturbing the telephone system.
CPE installations that include products which both transmit and receive binary data are generally connected to the telephone system through a device or circuit that performs both the MOdulation/DEModulation function. These devices are referred to as Data MODEMs. An RS-232 type cable normally connects an external stand alone MODEM to the DTE such as an Intelligent Work Station (IWS). A conventional telephone line cord is used to connect the MODEM to the customer loop. The modem function is sometimes packaged internally of the IWS.
One of the newer functions being provided by many telephone companies to customers is referred to as Caller-ID (CID). The CID concept involves transmitting the telephone number, i.e. the DN of the calling party, to the called party during the power ringing phase of the call. A CID processing device connected in parallel with the handset at the customer's premises displays the DN of the calling party without the called party's CPE switching from an "On-Hook" state to an "Off-Hook" state. The CID signal is sent to the CPE from the SPCS unit that services the called party as an FKS encoded binary signal that occurs between the first and second rings of the ringing cycle of the called equipment. The CID signal processing device, connected in parallel with the phone, demodulates the received FKS CID signal to provide a binary signal that is decoded and supplied to a display. The display may be a simple Liquid Crystal Display (LCD). This allows the called party to make a more informed decision as to whether or not to answer the phone. If the customer does not answer the phone, an "Off-Hook" signal is never sent to the SPCS unit so the ringing continues until the calling party hangs up or the call is answered by the customer's answering machine. The prior art discloses a number of arrangement in which a MODEM is connected to the telephone circuit through Data Access Arrangement (DAA) circuitry and its output is connected to a personal computer of IWS through an RS-232 cable or through the internal IWS bus for internal modems. The Modem circuitry is programmed to switch automatically from the "On-Hook" state to the "Off-hook" state following a predetermined number of rings. When the Modem goes "Off-Hook", a carrier signal, normally provided by the modem, alerts the calling equipment that a connection has been established and that the transmission of data can be negotiated.
The above system can be modified to display to the operator of the IWS, information that has been stored in the computer which is related in a predetermined fashion to the CID signal of the calling party. In a typical application, a mail order merchandising enterprise established a database in which each record represents a pending customer order. A record is addressable by the DN of the customer. The data of order receipt, date of shipment or the order, and date of expected arrival are maintained for each order along with any back order information. When a customer calls, the modem is initially connected to the system to receive and decode the CID signal. The decoded CID is transferred to the IWS where it is used to retrieve the corresponding record from the data base and to display it to the IWS operator. The operator then picks up the phone for voice communication with the customer and is in a position to immediately provide answers on the order status through. The operator's phone is connected to the telephone system in parallel with the modem. If the CID is not located in the database, the call is assumed to be a new order and is directed accordingly.
Since the standard CID signal is only transmitted between the first and second rings, when the telephone is connected in parallel with the CID processing device, there is a possibility for a party who is unfamiliar with the answering protocol to answer the call on the first ring and defeat the receipt of the CID. It is therefor desirable not to actuate the telephone ringing circuit until after the CID has been processed.
The present invention is therefore directed to providing a CID processing arrangement, at the CPE interface to the SPCS unit of the telephone system, that keeps the CPE "On-Hook" until after the CID signal is detected and processed and allows the telephone or other CPE to be selectively connected to the system only after the CID signal is processed.
A system and method which would provide automatic responses to calling parties based on selection criteria contained in CID addressable records of a database executed by an IWS would be advantageous. Applications similar to the above example of the merchandising enterprises that displays data to the IWS operator based on CID signal data could eliminate personal responses to many calls where the caller merchandise, for example, had already been shipped. An automatic voice response, stating the date of shipment and expected date of arrival could be provided based on data stored in the database and the processing of an algorithm involving the various date relationships. For example, if the database included data on when the order had been shipped, criteria could be established that could select a response statement setting forth the shipping date. Such criteria could, for example, consider the order date, the shipping date, the shipping time to the destination, the current date and an algorithm to test the time relationship among the criteria. If the time relationship was met, the "order shipping date" response would conclude with directions to the caller to follow, if the response was not adequate or additional information was required.
The present invention is therefore also directed to a system and method for providing an automatic voice response to a telephone call based on the CID of the calling party and other criteria that are employed to select at least one response from a plurality of stored responses. The present invention is readily distinguished from and should not be confused with, CPE equipment that does a call screening function based on the entry by the calling party, of a Password or Personal ID (PID) type data, after the receiving equipment switches to an "Off-Hook" state.